Friedrich Wilhelm III of Prussia

Friedrich Wilhelm III (3 August 1770-7 June 1840), also called Frederick William III or William III was the King of Prussia from 1797 until his death in 1840. He was best known for his involvement in the Battle of Jena-Auerstedt as an ally of the Fourth Coalition against the French Empire, and although he lost the battle, Prussia's involvement in the Napoleonic Wars contributed to Napoleon's downfall in 1815. He modernized Prussia's army, and his grandson Wilhelm I of Germany would use this army to conquer Austria and France in the 1860s and 1870s.